This invention relates to the field of metal door frame assemblies for mounting in door openings of walls which have a hollow space between spaced apart panels, sheets or other types of wall construction. They are commonly used for office partitions and inner office construction, to meet design needs of a particular tenant, which may change and usually does when one lease expires and a new tenant occupies the premises. For these and other reasons, the frame assemblies should be easy to assemble, require a minimum of labor expense, and have standardized component parts.
Examples of prior art door frame assemblies of this type include that disclosed in U.S. Pat. No. 4,308,692 wherein the upright members interengage with the top and bottom cross pieces to complete a relatively rigid rectangular frame. The U.S. Pat. No. 4,223,494 discloses a vinyl jamb which fits over a metal backing member, which in turn is fastened to the stud member. In U.S. Pat. No. 3,783,559, a door frame assembly is disclosed having web portions for securing hinge plates and striker plates. The U.S. Pat. No. 3,769,773 shows a metal door frame in which the cross-pieces have recesses for corresponding hooks in the upright members to seal. The U.S. Pat. No. 3,721,055 discloses a drywall door frame having slots in the upper ends of the jamb members to receive corresponding tongues of the cross-pieces. U.S. Pat. No. 3,469,350 discloses a door frame assembly in which the top cross-piece connects to the uprights by tabs inserted in corresponding slots. If also show a longtidunal door stop member which snaps in place on the upright jamb member. U.S. Pat. No. 3,385,004 discloses a door frame assembly having upwardly projecting tongues on the jambs and corresponding slots in each end of the top cross piece to connect it to the upright jamb membmers. It also includes Z-shaped stiffening members to stiffen the upright frame members. U.S. Pat. No. 3,320,705 discloses a fastening clip having cam surfaces which is nailed to the framing stud, and a metal frame member then pushed in place with its side walls being spread apart by the cam surfaces until they finally seat behind the fastening clip. U.S. Pat. No. 3,274,735 shows a facia strip snapped in place on a channel member as part of a door frame assembly. U.S. Pat. No. 3,130,455 discloses a plastic door frame having resilient side walls that spread apart and seat behind an anchoring strip nailed to the framing stud. U.S. Pat. No. 1,837,747, discloses an early type of metal door frame designed for use with plaster walls and having plaster terminals which are not connected, to help absorb the shock of door closures and prevent the shock waves from being transmitted to the plaster wall.
Each of the foregoing examples of prior art door frame assemblies disclose certain improvements and advances in this field. The present invention disclosed herein provides additional improvements and advances, in that the door frame assembly in accordance with the present invention can be secured to the framing studs by merely seating a projecting flange on one side of the stud in a groove on one side of the metal frame member, and pressing the other side of the metal frame member along a cammed surface until a groove on that side snaps in place over a projecting rib on the corresponding side of the stud. The studs and frame members have corresponding continuous ribs and grooves that mate with each other formed by the extrusion process. No tools are needed to mount the frame members in accordance with this invention to the corresponding framing studs.